37. Genus Streptococcus.

Question 1

Habitat Morphology and staining?

Answer 1

STREPTOCOCCUS
1. Habitat:
• skin, mucous membrane, food, milk
2. Morphology:
• spherical (coccus), chain, diplococci
• capsule:
• only on some species
• hyaluronic acid or polysaccharide
3. Staining:
• Gram-positive

Question 2

Streptococcus Culture\?

Answer 2

4. Culture:
   • fastidious:
   • blood agar, serum agar
   • some strains need CO2
   • selective culture:
   • crystal violet, thallium-SO4
   , esculin, blood (Edwards-agar)
   • haemolysis
   • α −haemolysis
   • β −haemolysis
   • no haemolysis (γ−haemolysis)

Question 3

Biochemistry?

Answer 3

5. Biochemistry:
   • catalase -, oxidase -, fermentative
   • utilisation of glycosides:
   • esculin
   • salicin
   • extra cellular enzymes:
   • fibrinolysin,
   • hyaluronidase,
   • nucleases,
   • proteases
   • toxins
   • some strains produce bacteriocins (probiotics)

Question 4

Antigens?

Answer 4

Antigens:
• complex
• group specific polysaccharide antigens
• Lancefield A-V
• other type specific antigens
• S. suis, S. pneumoniae: polysaccharide capsule antigens

Question 5

Resistance and pathogenecity?

Answer 5

7. Resistance:
• medium
8. Pathogenicity:
• local suppuration,
• metritis, mastitis, arthritis,
• septicaemia
• strangles
• pneumonic diseases
• virulence factors
• capsule
• toxins, haemolysines
• extra cellular enzymes
• some surface proteins

Question 6

Grouping?

Answer 6

Grouping:

• haemolysis • biochemical characteristics • antigens • genome structure • groups • pyogenic streptococci • oral streptococci • anginosus streptococci

Question 7

S.pyogenes?

Answer 7

. Species, pathogenicity
• S. pyogenes:
• capsule
• some strains produce erythrogen toxin
• bacteriophage encodes, phage conversion
• human
• scarlet fever
• purulent infections
• rheumatic fever
• human erysipelas (!)
• glomerulonephritis

Question 8

S. agalactiae, S. dysgalactiae subsp. dysgalactiae,S.uberis and s.equi?

Answer 8

10. Species, pathogenicity
    • S. agalactiae, S. dysgalactiae subsp. dysgalactiae, S. uberis:
    • cow, ruminants
    • mastitis
    • S. dysgalactiae subsp. equisimilis:
    • lymphadenitis, abortion (horse)
    • S. equi
    • S. equi subsp. equi: horse strangles
    • S. equi subsp. zooepidemicus:
    • in several animal species
    • suppuration, septicaemia, mastitis, abortion

Question 9

Species?

Answer 9

Species
• S. suis:
• septicaemia, arthritis, meningitis-encephalitis
• S. porcinus
• lymphadenitis, abscesses
• S. canis
• metritis, neonatal septicaemia
• S. salivarius, S. sanguis, S. mutans
• oral streptococci
• caries
• S. pneumoniae
• calf, foal, human: pneumonia, meningitis